If a user knows the keychain and can type it quickly, we shouldn't
annoy them with a popup. Only show the keyhint if the user doesn't
complete their keychain in 500ms.
The isVisible() check in the tests is somewhat invalid now because it
is never immediately visible and I don't want to add a delay to unit
tests. I added a check that text() is not set for one test that was
only checking isVisible().
Addresses part of #1515.
b1aaf0f10f